| 摘要 |
Disclosed herein are a high-density recording medium, such as a high-density optical disc and a recording and/or reproducing device therefor. At a transition area of the high-density optical disc allocated between a clamping area and an information area of the high-density optical disc is formed a step having a prescribed slope so that the high-density optical disc does not collide with an objective lens of an optical pickup provided in an optical disc device although the objective lens of the optical pickup is upwardly moved toward a recording layer of the high-density optical disc until it moves to the maximum working distance when the high-density optical disc, such as a Blu-ray disc, is improperly placed on a turntable provided in the optical disc device, e.g., when the high-density optical disc is placed upside down on the turntable. The thickness of the information area is smaller than that of the clamping area by the provision of the step at the transition area. Consequently, damage to the high-density optical disc or the objective lens due to a collision of the objective lens with the high-density optical disc is prevented, and fatal errors of a servo operation are effectively prevented. Furthermore, the cost of materials required to manufacture the high-density optical disc is reduced while stable clamping force is maintained, and safe insertion of the high-density optical disc into a slot-type optical disc drive is possible.
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